A Muslim covert who was jailed for trying to impose sharia law on Britain’s streets claims to have converted numerous prisoners to a radical form of Islam during his time behind bars, according to the Times.

Speaking to tonight’s BBC Panorama programme, Jordan Horner, who has taken the Islamic name Jamaal Udin, said that prison officers were powerless to stop him converting fellow inmates.

“The prison officers witnessed people become Muslim and in front of them I was giving them what we call Shahada, an invitation and acceptance of Islam,” he said.

“They was [sic] becoming Muslim in front of the prison officers and they felt sort of powerless. They said I was trying to divide Muslims from non-Muslims, trying to get them to follow an extreme version of Islam.”

He adds that he was moved three times in the space of year as prison officers tried to disrupt his activities.

Horner was jailed after his ‘sharia vigilante’ activities saw him threaten passers-by in London’s streets if they did not seem sufficiently Islamic. He and two other converts formed a self-styled “Muslim Patrol” and posted videos on YouTube showing them confronting people drinking in the street, women dressed ‘immodestly’, and also screaming ‘kill the non-believers’.

He was convicted of actual bodily harm after getting into a fistfight with a member of the public, and given a court order forbidding him from promoting sharia law for five years.

Also on tonight’s Panorama, Michael Coe, who converted to Islam while in prison, is shown meeting two convicted Islamist extremists upon his release. Coe, who takes the Islamic name Mikaeel Ibrahim, said that Islam was “the way to go”.

He was converted by the extremist Dhiren Barot, who is serving 30 years for plotting to bomb prominent New York landmarks.

Michael Spurr, chief executive of the National Offender Management Service, said that Islamic radicalisation in prisons poses a significant threat. He told the programme: “There is a significant risk, given the fact that we manage some very dangerous people. Our job is to minimise that risk becoming a reality — that somebody in prison becomes radicalised and commits a terrorist offence.”

Last month, the Prison Officers’ Association (POA) reported a surge in the number of “convenience Muslims” in Britain’s prisons, fuelling concerns about radical extremists threatening prison staff.

The POA’s head, Steve Gillan, said that staff faced a daily threat from Islamist groups, however he added that some prisoners converted to Islam for specific perks such as extra time outside cells for prayers, better food and to have the status of belonging to a particular gang.

The association added that some converts revert to their previous faith upon leaving prison, while others move to having no faith at all.

‘Panorama: From Jail to Jihad’ will be broadcast on BBC One at 8.30 tonight British Summer Time